/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FilterParentPath.java,v 1.2.4.1 2005/09/12 10:24:55 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ALOAD;
import com.sun.org.apache.bcel.internal.generic.ASTORE;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
import com.sun.org.apache.bcel.internal.generic.NEW;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
final class FilterParentPath extends Expression {

  private Expression _filterExpr;
  private Expression _path;
  private boolean _hasDescendantAxis = false;

  public FilterParentPath(Expression filterExpr, Expression path) {
    (_path = path).setParent(this);
    (_filterExpr = filterExpr).setParent(this);
  }

  public void setParser(Parser parser) {
    super.setParser(parser);
    _filterExpr.setParser(parser);
    _path.setParser(parser);
  }

  public String toString() {
    return "FilterParentPath(" + _filterExpr + ", " + _path + ')';
  }

  public void setDescendantAxis() {
    _hasDescendantAxis = true;
  }

  /**
   * Type check a FilterParentPath. If the filter is not a node-set add a
   * cast to node-set only if it is of reference type. This type coercion is
   * needed for expressions like $x/LINE where $x is a parameter reference.
   */
  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    final Type ftype = _filterExpr.typeCheck(stable);
    if (ftype instanceof NodeSetType == false) {
      if (ftype instanceof ReferenceType) {
        _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
      }
            /*
            else if (ftype instanceof ResultTreeType)  {
                _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
            }
            */
      else if (ftype instanceof NodeType) {
        _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
      } else {
        throw new TypeCheckError(this);
      }
    }

    // Wrap single node path in a node set
    final Type ptype = _path.typeCheck(stable);
    if (!(ptype instanceof NodeSetType)) {
      _path = new CastExpr(_path, Type.NodeSet);
    }

    return _type = Type.NodeSet;
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();
    // Create new StepIterator
    final int initSI = cpg.addMethodref(STEP_ITERATOR_CLASS,
        "<init>",
        "("
            + NODE_ITERATOR_SIG
            + NODE_ITERATOR_SIG
            + ")V");

    // Backwards branches are prohibited if an uninitialized object is
    // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed.
    // We don't know whether this code might contain backwards branches,
    // so we mustn't create the new object until after we've created
    // the suspect arguments to its constructor.  Instead we calculate
    // the values of the arguments to the constructor first, store them
    // in temporary variables, create the object and reload the
    // arguments from the temporaries to avoid the problem.

    // Recursively compile 2 iterators
    _filterExpr.translate(classGen, methodGen);
    LocalVariableGen filterTemp =
        methodGen.addLocalVariable("filter_parent_path_tmp1",
            Util.getJCRefType(NODE_ITERATOR_SIG),
            null, null);
    filterTemp.setStart(il.append(new ASTORE(filterTemp.getIndex())));

    _path.translate(classGen, methodGen);
    LocalVariableGen pathTemp =
        methodGen.addLocalVariable("filter_parent_path_tmp2",
            Util.getJCRefType(NODE_ITERATOR_SIG),
            null, null);
    pathTemp.setStart(il.append(new ASTORE(pathTemp.getIndex())));

    il.append(new NEW(cpg.addClass(STEP_ITERATOR_CLASS)));
    il.append(DUP);
    filterTemp.setEnd(il.append(new ALOAD(filterTemp.getIndex())));
    pathTemp.setEnd(il.append(new ALOAD(pathTemp.getIndex())));

    // Initialize StepIterator with iterators from the stack
    il.append(new INVOKESPECIAL(initSI));

    // This is a special case for the //* path with or without predicates
    if (_hasDescendantAxis) {
      final int incl = cpg.addMethodref(NODE_ITERATOR_BASE,
          "includeSelf",
          "()" + NODE_ITERATOR_SIG);
      il.append(new INVOKEVIRTUAL(incl));
    }

    SyntaxTreeNode parent = getParent();

    boolean parentAlreadyOrdered =
        (parent instanceof RelativeLocationPath)
            || (parent instanceof FilterParentPath)
            || (parent instanceof KeyCall)
            || (parent instanceof CurrentCall)
            || (parent instanceof DocumentCall);

    if (!parentAlreadyOrdered) {
      final int order = cpg.addInterfaceMethodref(DOM_INTF,
          ORDER_ITERATOR,
          ORDER_ITERATOR_SIG);
      il.append(methodGen.loadDOM());
      il.append(SWAP);
      il.append(methodGen.loadContextNode());
      il.append(new INVOKEINTERFACE(order, 3));
    }
  }
}
